SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cbee95bec5339d83de3bb19385855468ce3471b41dc767599d4981347e8b71c' 
  AND token = 'IbTfYMA9rMyvkTLN8miC3tr47YiqYRtuqLg79GnDGD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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