SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df32e0f7da25504c6c82e515fbb58043980338e0bf814ec625ff9c009541146' 
  AND token = 'qGmBv2vhLIFZiyrX+yBfB0zDub8FFKheU0/jQhYfVm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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