SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c10a2b3593cfeec0e9bd0a9b6e3653ccadac7cff5f70f252eb37958f0f8304' 
  AND token = 'kuoNIuO1meTaUSSAv4ctSHO9JqvWoRM3iwsaUN8eO7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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