SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa1cb2200c0df3067a6ed55fbf14a03489bccd49c5d9e64bca4536b675c85427' 
  AND token = 'gn3kJRJWkPoOmxPdoPtpo/vFFAzxDUUk4P49hKO5qI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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