SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd41baddb518d2a89c2b16b561cde0d7aee572712163af3c31639eed33ec35301' 
  AND token = 'iHXmKcKQweTT2wGHh/ICtUjUecqyubSXmoqYPU3qRoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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