SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1dcaca43f952fa01014f1ae7e8a699d3cb6ecdbd86f5bfe2724f45cfa522710' 
  AND token = 'lKt3molZSlIxDBXXWR4WBVXMuvrP61Wp/pfItxh/jTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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