SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33fff2be4879bf9cd8d2b629f40661efc99503b982410f81221914375bf06e71' 
  AND token = 'MckEWD9jc9ZcOs/AB/uRUSs1GRwXVQjq9t6vMsDU22o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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