SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '315153b721597777859e242cab9d54925943468081595241da2c399216f4f303' 
  AND token = 'CZs4MZe2IhxhaVYd7YNnnPZDmQiBUoGDTsSqOw8wt4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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