SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c412b979f13b4b73b8d44d654ad2b65d40d448c9e2d0d1c76b55094bdb7dda35' 
  AND token = 'eE/pTTzEsnRmqLONvsoIa6Z1QeW8iYz1VkEnykbamGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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