SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f39b38594dfa38163fc8afc3dc5f63a03025f913c4e353295842f01cf87208d3' 
  AND token = 'yT/Psgqm9AVxh/Wti5NDESDqAHB9yKR61575iRYUR48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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