SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959b7a6eb65895e12792f65170dbbad67a664976b9649983e08b2647dfb8eb5a' 
  AND token = '4WQdekQwHtiKtJGO45CAhOGxrGF/2X5jGcqIZKREdis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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