SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894bac5d470efcc90a7448b1b4e9c2b72496f41c9db2dd811220a6bc465c03d8' 
  AND token = 'fr9czNd9rOm9fQhzHGHVwHPNM0r4nERlSU6vThwF+d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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