SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f527faac4d104c4afea8ebccf929f878d12b40e02a014ad4fa8bc2fec4c69d9' 
  AND token = 'PkFHKYqSj8BkCZajQ9CjBTVp3ZJTzhlyNu91Q13xTZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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