SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d4039b5f00357bf9a72c59683370708c9c16c19e97c6a181340deb966a4fa79' 
  AND token = 'dFeSRxmUdOLYyw2ji2oCJgSY6jWNzLZvsm5cbhKY2gA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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