SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ead762c43e9e6155ae79ebd74293801f68c087d97663e7acf077cafd1702f6' 
  AND token = 'uHbJo7o22sgMVKbwxSwQnfIgziwAsxphkDglSAu6QPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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