SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ea93eba64ae7f70687768447003cd423ac11737dc872384a7c4a2871cfbadf9' 
  AND token = 'MVl8/daJtDkKjYSJ34CSQtFEDu6yOuMMZrLSceme3g8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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