SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a72df04c7959a8f273d3122dd5e88083c8882a8be092abd786f8a6242b75aebd' 
  AND token = 'sRCaVho4rcraFGl0nvl58ElFQlf//cZ6CyeCsekAmaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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