SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ad984eff78976d67065d788eb3683469f7fae09e01e6fa7629ba7976fe91ff' 
  AND token = 'dmbqvLr88+WUpu0ljVo0JZBRhz5O1g4ZnK5DJuX1CmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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