SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f8f313e6d7082e48560562de699c82ae664dd53a8fde5ec30b831795995d954' 
  AND token = 'AdsfKQ0owaOhnAFlBFc8cuT35vqjkIhXUEdorKqIZv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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