SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12cacd0fdc253f233d30f265708561aeb33dea72c1cb704b404280189500bc2c' 
  AND token = 'RZWmlda0II2jaJiJElVKdxuXzKyxwlZgUnV3aIjYges=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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