SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1617232358fb745bcd8e3ee964a3bac15132aeca53559683200c5433c1ca800' 
  AND token = '2E/urO/lPQpbi3rA0jbbPcLK7arUuQP0nCcNMOd5TUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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