SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c66d1aea115e5f24129583dd699e34bb9380dc454bb8940002eea751feab588' 
  AND token = 's94akw2yVPy0fSY1UZVbnMWgHid171+TCEGgPyGopnA=' 
  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"
    }
  }
}