SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aa89630a4dc64a31f2dbdf5ee92b22429e91c7e0d5f0de1cd480b4d5e0c6712' 
  AND token = '6ihucAlyDgg1Aa1cybNZkZm5LsE4hqOvIGmuIWIYpWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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