SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34fe881a8bc4466c9e348a1daae899f57b7e86d35244e2f043f1943db78bc78e' 
  AND token = 'YvWdILbUrRisZMv0TYzAm7AoSe9pEMdGYpJy+uvr9N4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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