SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89cf18107720435197b5b3def37cda365a7b179ad48cefe4becf26755c22a25b' 
  AND token = 'tVSKWAy+vEztKV+0LbvorCJsQzp/pIKOM+0b4PlwLsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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