SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd88ea7d4864c12f5f6a9fb63e254b38de8eba1a689157cb3b471a54383f3611c' 
  AND token = '/dL3Tt1JQfwJ5n20KqBvbR3VbwXCfjBqM9IswvS2UKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}