SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ee093c1ed3e696a2752ccd50807873042231186e8115c2cfcd4eed33ab4e3eb' 
  AND token = '6cJ+6t8NLrsrtVLEZknn3yJVLX+KY/6t/uFAmCpDUtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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