SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12493a063066b498e7e48bcf0d99cb447e3112a5fc543d7f56b1463d97d77862' 
  AND token = 's2lNtZiZ3j3Lc1QoVv7oK2+DNBOKUjfSvsZyEWxZeYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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