SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a4bf1c1484366954f165319dbe66aee696692d512e36e69b4a12d48725e7362' 
  AND token = 'axm5MWR8H4mtiZatdmLHLRtVhSZ6AcxbA/06p4sylQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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