SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b90b141bdabdd71a9229e5f7418c06a2dd7bdb364692980aa7fe7a4fc0defff' 
  AND token = 'xJh4/9Tc6wCTG0yYntVdnqBqkA3PTkjAzRKaUHG6ivQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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