SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19614606966089945574b4f37889a3973fccd7f3282aa4d1036dc910e546e5ed' 
  AND token = 'C0QEXXLBvcPM3M1gHUQllkWmA/FjfwnSoGwwTN+O07s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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