SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf7929392eb8a338d28c4c0203827cdefd059bc50184ecb10d9ccfcad651d529' 
  AND token = 'MCFM88cwTE1poHXV+Mg0c9NS3KvSE6EJG0ARuCXQTr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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