SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd787bf3f6298eef60dd691aee33dc2bfa700deeaa5bd853494660c9c31b2d6a6' 
  AND token = 'uwvN2P+KuZQajJzJ9rzN1XDNZ61DUR7OD0JZ6Z0GnKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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