SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8121e028fbf89b9afe4699d97155cdbf57b01e815b395f595438060710490d82' 
  AND token = 'rkjtv4Q4MjKYm+ynqPuRWWUYoPXXH2pARXuUCFzMFSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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