SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3ea1bce6c5c69d377eed59099b404b18aa1275ece309f5ce471d09ac7aa911c' 
  AND token = '+v3f6IRphCISwtXjqNwTon9520GQAv6w/80kYZJgy6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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