SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c3c62eca74f04723e69ab003e84b34c8cff328b7c1d6a9749fa556ed6c623e2' 
  AND token = 'ce/QjGvY/junzQVVV7hK6yLHBNV9K+IMjG5JDDYZxyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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