SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16f8d33960819a4384650b109f8aa1e91f29b7b95486786b9f72292be0fdc5f3' 
  AND token = 'UeJKkYEt9/NkbVVa/QuUJdv76Peo8Ek9pYlwaZwNKDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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