SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff463a7d63399435f3e100f1ae7ca6a5ea5bb275737426c2fcdc5086feefe53f' 
  AND token = 'G0/tOIj7Ph5IFxNV15ueH97RFBkpC5A+4YZx+rk6pb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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