SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c772f3d6d0236e05868f164295ada03515841a0a6d9427552bf524f4ba3caa4c' 
  AND token = 'ZWqJ74Fi0chfl9zk3ZVgvsNfL9aXSVNUbXdQBgfN0YA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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