SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2016d6d201485d95112a22782f50cad667ccc9022c979b21c55f0b2a36813ec2' 
  AND token = 'Z5eighGclVK6VFL5vuqc0Cw7eP/L3Jh9L/evZnddCDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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