SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96f49789a033b5a695c15c97a3a6979ed03773e1140af4ed8719d4612f5e00bf' 
  AND token = 'o11gxHZgL7ah6lRHm+pvChKmswtJTU/hTFRwvd8jS0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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