SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bd26b0ebd865d20cc44d52bfd19c1759c52f5c99f7c32561debfaa023112afe' 
  AND token = 'dU8hy4Cg5fAYnBxQlhqrBgyniBnBBR4sHf74sMXAMR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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