SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47435bdff3a6bc5988e66bbf47f9964ebae98ec88950843a735ca79ca8667844' 
  AND token = 'SIt9vYtIKULjY6rC1YQsL8AKGXPfW13z3ZwDWoV018o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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