SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15e7d1af5144cf0822cb354ebe56797dc7b803d6072e8aab7ea3df4ea2e648b4' 
  AND token = 'n0xcJgZy371fyLtCNO3Q0518nQ5o4Cu7/UkByBuLKrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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