SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a866d1442caf136386945301bc5fe81746ea746d86587e6245538a455fbe4ebf' 
  AND token = 'uC8OXO9j3yH4G5TP2GJ0Kf9poWshLITGscdBBqvsSaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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