SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaa8fa9e8a08d881b6305b13ce3d0f745f9837cad8c2605ab742c3f41f032600' 
  AND token = 'IoaMfxAdA2Ze61x8V0ulsPigGMKCIgpV8SEfsQn5i0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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