SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3436feb86d83d86afe30ecc5c4c0a007be629eacae369bb925bfd39b0970e7b7' 
  AND token = 'lrBVsLtGc8uBz86H9q+DXIQKdlblW1H2dRYbtKec6UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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