SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b287eadf86f41500bbfe45d948209447e63e6b525e28cd3317887f7532856969' 
  AND token = '0xaf7UQDFT0xGH+GeXXzJWucbmhmcuKkoCMKM3E1STM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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