SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b90e1bf01fc987422e34ca33674a49d4ad2bc59533bae9d5fb91b77337077a5' 
  AND token = 'Zh0sl2cCkjcMun3xVO+KdtrkgFPVogJQYi2X22zHCMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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