SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3392fde052903c0ad5928e8281a17860cbba6ecffa3f9e891fcd0c48f236872e' 
  AND token = 'miJkX3x0v1ZN/OCDGW1mXpFsxUU+/JPcnBRlCYzrKVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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