SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02c70138d8ef01b1d09e25c6979a06910ca055e65c24217d336f44a45b7dc090' 
  AND token = 'CtPoFbW7GtVTcxzYLaV/xkgZBKJWqUTh3IrXkVX1/G0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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