SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3126255d3876f547e70cc760642a81cc07a13506bf0b78db038765aabe27af16' 
  AND token = 'XNj4tGMPezhe+IHIKxxC+WFoBBYtuWXn80wEVshET3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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