SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675a5d9d21676c32e196ff501b90001b45ed277d956110ae5af06c8b7df215cd' 
  AND token = 'TAs4CbqX/KNo6gFbvbpcTpb815YUknay3JY89rDmABw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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