SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf54a40a17e7a5367f5c1d539bc829822c3ca0fe7d66995e823d780a6251de6d' 
  AND token = 'bEzG0uXmBfzDAPHG3dRAmh7uzzWCrrTOTVoy8Xx/OyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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