SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a65813db531840eb46ae4028216d84927d7ed4c563b106af528edb3a0cc17553' 
  AND token = '9JFMmgpo2L04ssyHe9M+OkLCZ6pIRyPjPeUlNCSNbrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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