SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd977621c1ce227e471ac1a662429f9afbe10ff75c81ff365766903e9894d6fdc' 
  AND token = 'YH0/eXLrbvh5IVm49pKZHMOkfMK4Iwb29lKF7wSWefU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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