SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fe1366c875bb30ee03cf0e230314244a1a4e68f9386754b1817e7a06d3eb73e' 
  AND token = 'RxPdxk3JasFWo/KZ/3fhhcuy0+NX3p7ZYWuIyODaJY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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