SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1810e78056f8da1abae7a40f94fa9d09ae067a71a8596a989fca458f292afb8a' 
  AND token = '6TfXIiiDqRZqmjj5/8379hvhtiecnXxtppieaS+IQrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}