SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2724ecda80cbc301c12537bf8456bbe57ff0439b261adb73328e52ff9346cb5' 
  AND token = 'Kqz/7lFZBNXpbwK+Qwg6bUeUiEmr09W6MIDVe92dqac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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