SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c1037be6998dc374d0078d41eefffe765dc48160a9b7ea9ef98a8414f512289' 
  AND token = 'q2Qgv13ADZ6YY6cf5IgxmVrl15/afNexVYz0vwKj0GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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