SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '050b7b7914710fe3ae681c4d0f4ddfece41c5a82783065dafadbbce46363c250' 
  AND token = 'gxh3WePrDr/Sok+/FALkiLqiLs44e1vJJTNxovdjLMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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