SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2898a37761c5735a8159aad7e4d9328f46653dd2fa0c3bb9fd3411e243c42519' 
  AND token = 'Y8fLXbyTGxQbZM8QBDrVpS35KtlfGv1YEqbJnzTY+Sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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