SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e99c301e76106e4668fea7c0bf023cc93a904abd450359dd382d0927ac2d8820' 
  AND token = 'tctODJb4S2KEULwAUoisDLtt60ajS3+r0nA+6v6jowk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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