SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6846fabab9d2e3aeb85c9d54e88c529bb7bb6046e7c955751c094f4c0065bdc0' 
  AND token = 'JpoOTrYISLGRKelY9Gsve1iuNYvHzWd3867HpQ9/GiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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