SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27103ee5830e3ffb9bfe5e72543955d3a2bcb17a87cad6a00dc33e13fe890ff1' 
  AND token = 'QEU4/GZ1UuPwvaykRp5OAjKppMTLWzfOXCvZBNzq9+k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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