SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7409b221119d76089b4b2b760a2f3ba5b36a4ff2b80c02cbb5552b5bfecd4532' 
  AND token = 'QkpcLzKimCzqCGxujJI70u2P+1qb+GN745NmMBNQ2TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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