SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ea3efd88d141245e25eb2688aa7ecc6e55212b6f78a04d0ccb3f02964227ba' 
  AND token = 'c04gyQUoTifvvP+qtR7SAUsmQhzEperPV0XK9UTeEpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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