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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '687aa54353bfbc01bca858d6ed0929e2ebd4f2f11af67c26bcbc27bdca53c549' 
  AND token = 'eCViqU980m8MG4OzQ4OmHTa2UHZEkGUyYb8v1fjP1Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}