SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6f75414402dcf7d53352ab584268181a94b8ae67ee2947c1403eeba3dba0836' 
  AND token = 'zo84VaaKTRtbcLUX9TQWFhAL49Dt/JsFMaj2PnybiDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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