SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f57982423837e97e2098dbf3778507fed156e2bedd1b9db17cd8bc7c971c8f6b' 
  AND token = 'RmeUQdAnz4EnmN6fX+tscYIPui/Hs6XNV5PjN6H7Up0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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